1. Field of the Invention
The invention relates to novel use of the compounds of formula (I) in treating mammalian subjects, including humans, suffering from diseases or conditions which are characterized by reduced blood flow, oxygen availability or carbohydrate metabolism in the cardiovascular system, or other diseases involving defects in carbohydrate metabolism, particularly obesity and diabetes. The compounds of formula (I) are well known in the art and methods for optical resolution of the racemic mixtures to obtain the L-isomers have been reported in, for example, U.S. Pat. Nos. 3,976,680 and 4,016,205 and references cited therein.
2. Description of the Prior Art
As mentioned above, the compounds of formula (I) are known compounds. Methods for the preparation of racemic 2-(4-hydroxyphenyl)glycine and 2-(4-methoxyphenyl)glycine and their esters as well as the resolution of the esters into the D- and L-enantiomers are described in U.S. Pat. No. 3,976,680. The same reference provides methods for hydrolysis of the resolved esters to provide the optically active acids of formula (I).
U.S. Pat. No. 4,016,205 discloses a process for resolving D- and L-2-(4-hydroxyphenyl)glycine and reviews the prior art chemical and enzymatic methods for the resolution of the D-isomer.
The amides of formula (I) are readily obtained, for example, from the corresponding acids via the acid chlorides by well-known methods, or from the corresponding lower alkyl esters such as the methyl ester, by treatment with ammonia as described by Neilson and Ewing, Jour. Chem. Soc., Part C, 393 (1966) for preparation of optically active phenylglycines.
While the DL- and D- forms of the acids of formula (I) are known in the art to be useful intermediates in the preparation of penicillins and cephalosporins, no medical or any other use has been proposed for the L-isomers of formula (I), or any medical use for the racemic forms of these compounds.